This invention relates generally to a fall-arrest system and more particularly to a system having an intermediate support for a horizontal lifeline and a worker""s lifeline connector which allows the connector to pass through the intermediate support without disconnecting and reconnecting around the support.
Under normal working conditions, a worker on a scaffold, catwalk or other walkway positioned in a relatively high place where a fall could result in serious injury, will wear some type of safety harness which is slidingly coupled to a horizontal lifeline. Typically, the horizontal lifeline is connected between two anchor supports. Either one of two known methods is used to eliminate sag in the lifeline. One known method is to tighten the lifeline until all sag has been eliminated. However, this method can produce very large forces on the anchor supports which may not be acceptable. Another known method is to use intermediate supports. The intermediate supports divide the span into a plurality of smaller spans so less force is needed at the anchor supports. One such intermediate support device is illustrated in U.S. Pat. No. 4,584,945 which shows a system for transferring a load across a corner support for a lifeline using a rotatable wheel having a plurality of projections and a cooperating sliding element. The sliding element, not the rotatable wheel, supports the lifeline as a worker""s lifeline connector slides along the lifeline over the sliding element and rotates the wheel. The rotatable wheel is attached to an anchor support through its axle which allows the worker to pass back and forth around the support. A disadvantage associated with this type of system is a low strength rating. The sliding element is attached to the rotating wheel by steel tabs which must bear a worker""s weight when the worker falls, thus limiting the system to two workers at a time.
Another type of intermediate support device is illustrated in U.S. Pat. No. 5,343,975 in which a long tube protrudes from an anchor bar support to support a lifeline. As a C-shaped worker""s connector nears the support, the cammed edge on the connector rotates the connector so the opening of the C matches the anchor bar. The anchor bar support is designed to deform during a fall to absorb energy. One disadvantage associated with this type of system is the down time required after a worker falls. All of the anchor bar supports must be removed and replaced by the manufacturer before workers can use the lifeline again.
A need therefore exists for a fall-arrest system having an increased strength rating and a decreased down time in the event of a fall.
According to the present invention, there is provided a fall arrest system for a horizontal lifeline in which a rotatable star wheel mounted on an anchor body contacts and supports the horizontal lifeline. Preferably there is a pair of cooperating rotatable star wheels which contact and support the horizontal lifeline at intermediate points such that a glider connector attached to a worker""s lifeline may pass through the rotatable star wheels. The rotatable star wheels are fixed to an intermediate anchor support and are angled relative to each other. A plurality of projections of the star wheels mesh together somewhat like a gear and form a V on which the lifeline is directly supported. At least one rail provided on the intermediate anchor support lifts at least one wheel of a glider connector off of the lifeline as the glider connector nears the intermediate anchor support body. Once the glider connector has sufficiently moved up the at least one rail, an arm of the glider connector contacts the projections of the star wheels.
As the worker walks parallel to the lifeline, the force of the moving worker is greater than the friction on the star wheels (due to the weight of the lifeline) causing the star wheels to rotate while the glider connector moves. As the star wheels rotate, a space is created between the projections of one star wheel relative to the other star wheel. The glider connector arm will move through the projections in this space. Once the star wheels have rotated sufficiently so that there are no projections contacting the glider connector arm anymore, the glider connector will continue to roll down the at least one rail and back onto the lifeline.
The system of the present invention provides increased strength and allows up to five workers on a single lifeline, with a maximum of two workers on a span. Additionally, the system allows for a single worker fall with no permanent deformation of the intermediate support. This greatly reduces the amount of time the system will be out of use after a worker fall. The present invention requires little more than inspection by a qualified person before being brought back into use after a single worker fall.